Main phase 1 and 2 are the same phases. You summon and activate spells/traps in them.
The only time where you can't activate a card in one of those two phases is when the card specifically says so.
Example:
Cardcar D :
Cannot be Special Summoned. During your Main Phase 1, if this card was Normal Summoned this turn: You can Tribute this card; draw 2 cards, then it becomes the End Phase of this turn. You cannot Special Summon during the turn you activate this effect.
Not how it specifically states Main Phase 1.
Emergency Assistance :
Activate during your Main Phase 2, to Special Summon 1 Level 4 monster from your Graveyard that was destroyed by a card effect and sent to the Graveyard this turn.
States Main Phase 2.
guardian sphinxThu Mar 21, 2013 6:01 pm